## Copyright (C) 1995, 1996, 1997 Kurt Hornik ## ## This program is free software; you can redistribute it and/or modify ## it under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 2, or (at your option) ## any later version. ## ## This program is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with this file. If not, write to the Free Software Foundation, ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ## usage: f_rnd (m, n [, r, c]) ## ## f_rnd (m, n) returns a matrix of random samples from the F ## distribution with m and n degrees of freedom. The size of the matrix ## is the common size of m and n. ## ## f_rnd (m, n, r, c) returns an r by c matrix of random samples from ## the F distribution with m and n degrees of freedom. Both m and n ## must be scalar or of size r by c. ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> ## Description: Random deviates from the F distribution function rnd = f_rnd (m, n, r, c) if (nargin == 4) if ( !(is_scalar (r) && (r > 0) && (r == round (r))) ) error ("f_rnd: r must be a positive integer"); endif if ( !(is_scalar (c) && (c > 0) && (c == round (c))) ) error ("f_rnd: c must be a positive integer"); endif [retval, m, n] = common_size (m, n, zeros (r, c)); if (retval > 0) error (strcat("f_rnd: ", "m and n must be scalar or of size ", sprintf ("%d by %d", r, c))); endif elseif (nargin == 2) [retval, m, n] = common_size (m, n); if (retval > 0) error ("f_rnd: m and n must be of common size or scalar"); endif else usage ("f_rnd (m, n [, r, c])"); endif [r, c] = size (m); s = r * c; m = reshape (m, 1, s); n = reshape (n, 1, s); rnd = zeros (1, s); k = find (!(m > 0) | !(m < Inf) | !(m == round (m)) | !(n > 0) | !(n < Inf) | !(n == round (n))); if (any (k)) rnd(k) = NaN * ones (1, length (k)); endif k = find ((m > 0) & (m < Inf) & (m == round (m)) & (n > 0) & (n < Inf) & (n == round (n))); if (any (k)) rnd(k) = f_inv (rand (1, length (k)), m(k), n(k)); endif rnd = reshape (rnd, r, c); endfunction

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